Defense attorneys for the man accused of murdering Phylicia Barnes have filed motions claiming to have a witness who saw the teen alive in Cecil County and attacking the credibility of the lead police detective who investigated the case.

In a motion filed in Baltimore Circuit Court, defense attorneys for Michael Maurice Johnson say they intend to call an "alibi witness" named Robert Hickman Fields when the case comes to trial in January. Johnson was charged with murder April 25 in the high-profile disappearance of the North Carolina teen.

Asked to clarify the filing, defense attorneys Ivan Bates and Russell Neverdon said that Fields saw the 16-year-old Barnes — and not Johnson — in Cecil County in the days after she was reported missing. Fields could not be reached for comment.

The attorneys are also asking the court to compel the Baltimore Police Department to turn over internal affairs records related to Daniel T. Nicholson IV, the lead detective in the case. The day before Johnson was charged with murder, Nicholson was suspended by the agency.

At the time, law enforcement sources said Nicholson had led a rogue hunt for his own missing teenage daughter. On Tuesday, city prosecutors said the case remained under investigation.

The records may "clarify the possible connection between the detective's suspension and Mr. Johnson's hasty indictment," a court filing says, adding that the search for his daughter and the tactics used to investigate Barnes' disappearance could "show the pattern of misconduct Detective Nicholson uses in cases such as these."

Through an attorney, Nicholson has denied wrongdoing, and the city police union has supported him, saying he did what any concerned father would have done. His attorney, Matthew Fraling, said Nicholson did nothing inappropriate and called the accusations contained in the defense motion "absolutely ludicrous."

In the Barnes case, prosecutors allege that Johnson asphyxiated Barnes, then moved her body by placing it inside a 35-gallon plastic tub. A neighbor, they said in court this summer, saw Johnson sweating and struggling to move a tub out of the apartment of Barnes' older half-sister.

In court papers, his attorneys say Johnson — the last person known to have seen Barnes alive — was interviewed by detectives on Jan. 3, 2011, after being taken in involuntarily. Johnson, his brother Glenton and cousin Kevin Johnson were put in "flex cuffs" and taken by van to the police station, where they were put in separate rooms for interviews and not read their Miranda rights or allowed to call a lawyer, the filings say.

Johnson was held for 17 hours, from 6 p.m. Jan. 3 until 11 a.m. the next day, his attorneys say.

"Mr. Johnson was kept in handcuffs and chained to the bench he was sitting on," according to court documents. "The detectives grilled him about the victim and accused him of 'having a thing for her.' … There is no recording or transcript of the interview as well as no officer's notes that were provided in discovery by the state."

In a letter to Johnson's attorneys, prosecutors confirmed that he was at the homicide offices on Jan. 3. Officials did not respond to a request for comment on the case.

The attorneys also claim that Nicholson at one point took Johnson's vehicle without permission and without a warrant, and eventually returned it to him. "This interaction was only the beginning of Detective Nicholson's constant and consistent menacing and intimidating behavior towards the [sic] Mr. Johnson."

They say that Nicholson "made numerous phone calls to Mr. Johnson's work, showed up [at] his job and repeatedly attempted to contact him."

On April 20, 2011, Barnes' body was found floating in the Susquehanna River. On Sept. 22, 2011, Nicholson was charged in Baltimore County on allegations that he struck his daughter with a coaxial cable, a case that was dropped on condition that the family attend counseling.

Attorneys claim that in October and November, prosecutors in Harford County — where Barnes' body was found — took the case before a grand jury but did not file charges.

On April 20, 2012, Nicholson's daughter ran away from home, and police were investigating whether he improperly used department resources to search for her. Occupants of a Northeast Baltimore home reported to police that several men entered their apartment, and Nicholson was picked out of photo lineups. Police said they took a 911 call for assault at the home.

The day after Nicholson was suspended, charges were filed against Johnson. Internal affairs records, the defense attorneys say, "will assist the jury in determining the credibility" of Nicholson and other officers involved in the case.

Several motions have been filed since Johnson was charged, including at least two by prosecutors seeking GPS data from two cell phones between Jan. 1, 2010, and July 29, 2010.